PN code based addressing methods and apparatus for airlink communications

ABSTRACT

Methods and apparatus for communicating between an access terminal (AT) and an Access Point (AP) are described. For communications over the air link, between an AP and an AT a PN (Pseudo-random Noise) code based address is used as an AP identifier, e.g., address. The PN code based address may be based on Pilot PN code based signals received from an AP. Thus, the PN based AP address may be determined from pilot signals received from an AP. The PN based AP address may be a shortened version of a PN code corresponding to an AP, a full PN code corresponding to an AP, or a value which can be derived in a known manner from a PN code corresponding to an AP.

RELATED APPLICATIONS

The present application claims the benefit of U.S. Provisional PatentApplication Ser. No. 60/812,011 filed on Jun. 7, 2006, titled “A METHODAND APPARATUS FOR L2TP TUNNELING” and the benefit of U.S. ProvisionalPatent Application Ser. No. 60/812,012 filed on Jun. 7, 2006 titled “AMETHOD AND APPARATUS FOR ADDRESSING MULTIPLE ACCESS POINTS” each ofwhich is hereby expressly incorporated by reference.

FIELD

The present invention is directed to methods and apparatus forcommunications, and more particularly to methods and apparatus relatedto routing of packets.

BACKGROUND

Wireless communications systems often include a plurality of accesspoints (APs) and/or other network elements in addition to accessterminals, e.g., mobile or other end node devices. In many cases accessterminals normally communicate with access points via wirelesscommunications links while other elements in the network, e.g., APs,generally communicate via non-air links, e.g., fiber, cable or wirelinks. In the case of an airlink, bandwidth is a valuable constrainedresource. Accordingly, it is desirable that communication over theairlink be performed in an efficient manner without excessive overhead.

Communications links between access points and/or other network devicesare often less constrained from a bandwidth perspective than are airlinks between access terminals and access points. Accordingly, moreoverhead in terms of address length and/or other information may beacceptable over backhaul links than over an airlink.

While IP addresses have been used successfully in networks for manyyears, they tend to include a fair number of bits. For communicationsover airlinks, it would be desirable if shorter addresses could be usedover the airlink. However, it would be desirable that any changes toaddresses used over the airlink not preclude the use of IP addressesover other links, e.g., backhaul links.

SUMMARY

Methods and apparatus for communicating between an access terminal (AT)and an Access Point (AP) are described. For communications over the airlink, between an AP and an AT a Pilot PN code based address is used asan AP identifier, e.g., address. The pilot PN code is an pilotidentifier that is used to distinguish the pilot channel or channelstransmitted by different access points or sectors. When the pilotchannel uses a Pseudorandom Noise (PN) type of generation scheme, thisidentifier is typically called a PilotPN. In this application, the term“PN Code” refers to a generic pilot identifier and a PN Code addressrefers to an address based on a PN Code.

Other examples of pilot generation include Gold sequence, Beacon basedpilots etc. and in such cases a PN Code address refers to an addressbased on an identifier communicated by the type of pilots being used.

The PN code based address may be based on Pilot PN code based signalsreceived from an AP. Thus, the PN based AP address may be determinedfrom pilot signals received from an AP. The PN based AP address may be ashortened version of a PN code corresponding to an AP, a full PN codecorresponding to an AP, or a value which can be derived in a knownmanner from a PN code corresponding to an AP. By using a PN code basedvalue as an address for an AP, an AT can identify an AP in an airlinkcommunication without having to use an IP address corresponding to theAP. In addition, PN based addressing has the advantage of usinginformation readily available to an AT since this information can beobtained or derived from signals normally transmitted to an AT for otherreasons. Thus, an AT can identify a local or remote AP to a serving APwith which the AT has an active connection without having to go throughan IP address discovery process or other addressing update process.Furthermore, because the PN code based identifier being used forcommunications over an airlink can be shorter than a full IP address ofan AP, efficient use of the airlink can be achieved.

The PN coded based address used to identify an AP can be used by theserving AP for downlink transmission and/or by an AT for uplinktransmission. In the case of downlink transmissions, the serving APindicates the source of the payload being transmitted, e.g., a remote APor the local serving AP, by including the PN code based addresscorresponding to the sending device. For example, when a packet payloadcorresponding to a remote AP, communicated to the serving AP via a Layer2 tunnel, the serving AP determines the PN code based address used toidentify the remote AP from the remote AP's IP address. This may be doneusing a look-up table maintained by the serving AP which includes IPdevice address information and corresponding PN code identifierinformation. The look-up table allows a serving AP to map between deviceIP and PN code addresses thereby allowing an IP address to be determinedfrom the PN code identifier or the PN code identifier to be determinedfrom an IP address. In some embodiments the actual PN code addressesused over the airlink are stored in the look-up table. However, thestored PN code information may be a value, e.g., the PN code of an AP,from which the PN code address for airlink communications can bederived, e.g., in a known manner, e.g., by truncation and/or through useof a predetermined formula. In some embodiments, the look-up table maybe maintained based on address and PN code information transmitted viabackhaul communications links connecting various network devices, suchinformation may be sent as part of routing update information, initialAP device configuration information and/or through other techniques. Forexample, in some embodiments, APs are initially provisioned withinformation on the PN codes used by neighboring, e.g., physicallyadjacent, APs and their corresponding IP addresses.

In the case of uplink signals, an AT uses the PN code based address toidentify the destination device to which a transmitted payload, e.g.,the payload of a MAC (Media Access Control) packet, is to becommunicated. The destination device identified by the PN code addressmay be a remote AP or the currently serving AP to which the packet iscommunicated over an airlink. Upon receiving a packet from an AT, theserving AP determines if the packet corresponds to a remote AP and, ifso, in some embodiments then determines the corresponding long, e.g., IP(Internet Protocol) address, of the destination AP from the PN codeidentifier received over the airlink. The received packet payload isthen forwarded to the destination AP using the determined IP address asthe destination address of the packet being sent. The packet may, and invarious embodiments is, communicated to the destination AP identified bythe determined IP address via a Layer 2 tunnel used for communicatingpackets between the remote AP and the serving AP.

In this manner, an AT can communicate over the airlink using fewer bitsto identify a destination device than would be required if a longaddress, e.g., the full IP address of the destination device, was usedfor communications over an airlink between a serving AP and an AT.

An exemplary method of communicating information to an access terminalcomprises: generating a packet, said packet including a PN code addressidentifying an access point and information to be communicated to saidaccess terminal; and transmitting said generated packet over an airlinkto said access terminal. An exemplary method of operating an accesspoint to communicate information to a remote access point comprises:receiving a packet from an access terminal, said packet including a PNcode address and information to be communicated to a remote device;determining a long address corresponding to said PN code address to beused for communicating a packet to said remote device, said long addressincluding more bits than said PN code address; and sending saidinformation to be communicated, with the long address, to said remotedevice. An exemplary access point for communicating information to anaccess terminal, comprises: a network interface for receiving a packetfrom a remote device via a network connection, said packet including along address and information to be communicated; a long address to PNcode address mapping module for determining a PN code addresscorresponding to said long address, said PN code address for use over awireless communications link, said PN code address including fewer bitsthan said long address; a downlink packet generation module forgenerating a packet including said PN code address and said informationto be communicated; and a wireless transmitter for transmitting, oversaid wireless communications link, downlink packets.

An exemplary method of operating an access terminal to communicateinformation comprises: receiving a signal from a device; generating a PNcode address from said received signal; and generating a packetincluding said PN code address, said packet being directed to saiddevice. An exemplary method of operating an access terminal to receiveinformation from a remote device through an access point comprises:receiving from said access point a packet including a PN code addresscorresponding to said remote device and information from said remotedevice; and identifying the remote device which provided the informationfrom said PN code address and stored information relating the receivedPN code addresses to an access point. An exemplary access terminal forcommunicating information to a remote device through an access pointcomprises: a packet generation module for generating a packet includingan PN code address corresponding to said remote device and informationto be communicated to said remote device; and a wireless transmitter fortransmitting the generated packet over the air to said access point.

While various embodiments have been discussed in the summary above, itshould be appreciated that not necessarily all embodiments include thesame features and some of the features described above are not necessarybut can be desirable in some embodiments. Numerous additional features,embodiments and benefits are discussed in the detailed description whichfollows.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a multiple access wireless communication systemaccording to one embodiment.

FIG. 2 is a block diagram of an exemplary communication system.

FIG. 3 illustrates an exemplary network including a distributed accessnetwork (AN) architecture and an access terminal (AT).

FIG. 4 illustrates an exemplary network including a centralized ANarchitecture and an AT.

FIG. 5 is a flowchart of an exemplary method of operating an accesspoint to communicate information to an access terminal in accordancewith various embodiments.

FIG. 6 is a flowchart of an exemplary method of operating an accesspoint to communicate with a remote access point.

FIG. 7 is a drawing of an exemplary access point in accordance withvarious embodiments.

FIG. 8 is a flowchart of an exemplary method of operating an accessterminal to communicate information in accordance with variousembodiments.

FIG. 9 is a flowchart of an exemplary method of operating an accessterminal to receive information from a remote device through an accesspoint.

FIG. 10 is a drawing of an exemplary access terminal in accordance withvarious embodiments.

DETAILED DESCRIPTION

Wireless communication systems are widely deployed to provide varioustypes of communication content such as voice, data, and so on. Thesesystems may be multiple-access systems capable of supportingcommunication with multiple users by sharing the available systemresources (e.g., bandwidth and transmit power). Examples of suchmultiple-access systems include World Interoperability for MicrowaveAccess (WiMAX), infrared protocols such as Infrared Data Association(IrDA), short-range wireless protocols/technologies, Bluetooth®technology, ZigBee® protocol, ultra wide band (UWB) protocol, home radiofrequency (HomeRF), shared wireless access protocol (SWAP), widebandtechnology such as a wireless Ethernet compatibility alliance (WECA),wireless fidelity alliance (Wi-Fi Alliance), 802.11 network technology,public switched telephone network technology, public heterogeneouscommunications network technology such as the Internet, private wirelesscommunications network, land mobile radio network, code divisionmultiple access (CDMA), wideband code division multiple access (WCDMA),universal mobile telecommunications system (UMTS), advanced mobile phoneservice (AMPS), time division multiple access (TDMA), frequency divisionmultiple access (FDMA), orthogonal frequency division multiple access(OFDMA), global system for mobile communications (GSM), single carrier(1X) radio transmission technology (RTT), evolution data only (EV-DO)technology, general packet radio service (GPRS), enhanced data GSMenvironment (EDGE), high speed downlink data packet access (HSPDA),analog and digital satellite systems, and any othertechnologies/protocols that may be used in at least one of a wirelesscommunications network and a data communications network.

Generally, a wireless multiple-access communication system cansimultaneously support communication for multiple wireless terminals.Each terminal communicates with one or more base stations viatransmissions on the forward and reverse links. The forward link (ordownlink) refers to the communication link from the base stations to theterminals, and the reverse link (or uplink) refers to the communicationlink from the terminals to the base stations. This communication linkmay be established via a single-in-single-out, multiple-in-signal-out ora multiple-in-multiple-out (MIMO) system.

Referring to FIG. 1, a multiple access wireless communication systemaccording to one embodiment is illustrated. An access point 100 (AP)includes multiple antenna groups, one including 104 and 106, anotherincluding 108 and 110, and an additional including 112 and 114. In FIG.1, only two antennas are shown for each antenna group, however, more orfewer antennas may be utilized for each antenna group. Access terminal116 (AT) is in communication with antennas 112 and 114, where antennas112 and 114 transmit information to access terminal 116 over forwardlink 120 and receive information from access terminal 116 over reverselink 118. Access terminal 122 is in communication with antennas 106 and108, where antennas 106 and 108 transmit information to access terminal122 over forward link 126 and receive information from access terminal122 over reverse link 124. In a FDD system, communication links 118,120, 124 and 126 may use different frequencies for communication. Forexample, forward link 120 may use a different frequency then that usedby reverse link 118.

Each group of antennas and/or the area in which they are designed tocommunicate is often referred to as a sector of the access point. In theembodiment, antenna groups each are designed to communicate to accessterminals in a sector of the areas covered by access point 100.

In communication over forward links 120 and 126, the transmittingantennas of access point 100 utilize beamforming in order to improve thesignal-to-noise ratio of forward links for the different accessterminals 116 and 122. Also, an access point using beamforming totransmit to access terminals scattered randomly through its coveragecauses less interference to access terminals in neighboring cells thanan access point transmitting through a single antenna to all its accessterminals.

An access point may be a fixed station used for communicating with theterminals and may also be referred to as an access node, a Node B, abase station or some other terminology. An access terminal may also becalled an access device, user equipment (UE), a wireless communicationdevice, terminal, wireless terminal, mobile terminal, mobile node, endnode or some other terminology.

FIG. 2 is a block diagram of an embodiment of an exemplary access point210 and an exemplary access terminal 250 in a MIMO system 200. At theaccess point 210, traffic data for a number of data streams is providedfrom a data source 212 to a transmit (TX) data processor 214.

In an embodiment, each data stream is transmitted over a respectivetransmit antenna. TX data processor 214 formats, codes, and interleavesthe traffic data for each data stream based on a particular codingscheme selected for that data stream to provide coded data.

The coded data for each data stream may be multiplexed with pilot datausing OFDM techniques. The pilot data is typically a known data patternthat is processed in a known manner and may be used at the receiversystem to estimate the channel response. The multiplexed pilot and codeddata for each data stream is then modulated (i.e., symbol mapped) basedon a particular modulation scheme (e.g., BPSK, QSPK, M-PSK, or M-QAM)selected for that data stream to provide modulation symbols. The datarate, coding, and modulation for each data stream may be determined byinstructions performed by processor 230.

The modulation symbols for each of the data streams are then provided toa TX MIMO processor 220, which may further process the modulationsymbols (e.g., for OFDM). TX MIMO processor 220 then provides N_(T)modulation symbol streams to N_(T) transmitters (TMTR) 222 a through 222t. In certain embodiments, TX MIMO processor 220 applies beamformingweights to the symbols of the data streams and to the antenna from whichthe symbol is being transmitted.

Each transmitter (222 a, . . . , 222 t) receives and processes arespective symbol stream to provide one or more analog signals, andfurther conditions (e.g., amplifies, filters, and upconverts) the analogsignals to provide a modulated signal suitable for transmission over theMIMO channel. N_(T) modulated signals from transmitters 222 a through222 t are then transmitted from N_(T) antennas 224 a through 224 t,respectively.

At access terminal 250, the transmitted modulated signals are receivedby N_(R) antennas 252 a through 252 r and the received signal from eachantenna 252 is provided to a respective receiver (RCVR) 254 a through254 r. Each receiver (254 a, 254 r) conditions (e.g., filters,amplifies, and downconverts) a respective received signal, digitizes theconditioned signal to provide samples, and further processes the samplesto provide a corresponding “received” symbol stream.

An RX data processor 260 then receives and processes the N_(R) receivedsymbol streams from N_(R) receivers (254 a, . . . , 254 r) based on aparticular receiver processing technique to provide N_(T) “detected”symbol streams. The RX data processor 260 then demodulates,deinterleaves, and decodes each detected symbol stream to recover thetraffic data for the data stream. The processing by RX data processor260 is complementary to that performed by TX MIMO processor 220 and TXdata processor 214 at transmitter system 210.

A processor 270 periodically determines which pre-coding matrix to use(discussed below). Processor 270 formulates a reverse link messagecomprising a matrix index portion and a rank value portion.

The reverse link message may comprise various types of informationregarding the communication link and/or the received data stream. Thereverse link message is then processed by a TX data processor 238, whichalso receives traffic data for a number of data streams from a datasource 236, modulated by a modulator 280, conditioned by transmitters254 a through 254 r, and transmitted, via antennas (252 a, 252 r),respectively, back to access point 210.

At access point 210, the modulated signals from access terminal 250 arereceived by antennas 224, conditioned by receivers 222, demodulated by ademodulator 240, and processed by a RX data processor 242 to extract thereverse link message transmitted by the receiver system 250. Processor230 then determines which pre-coding matrix to use for determining thebeamforming weights, then processes the extracted message.

Memory 232 includes routines and data/information. Processors 230, 220and/or 242 execute the routines and uses the data/information in memory232 to control the operation of the access point 210 and implementmethods. Memory 272 includes routines and data/information. Processors270, 260, and/or 238 execute the routines and uses the data/informationin memory 272 to control the operation of the access terminal 250 andimplement methods.

In an aspect, SimpleRAN is designed to significantly simplify thecommunications protocols between the backhaul access network elements ina wireless radio access network, while providing fast handoff toaccommodate the demands of low latency applications, such as VOIP, infast changing radio conditions.

In an aspect, the network comprises access terminals (AT) and an accessnetwork (AN).

The AN supports both a centralized and distributed deployment. Thenetwork architectures for the centralized and distributed deploymentsare shown in FIG. 3 and FIG. 4 respectively.

FIG. 3 illustrates an exemplary network 300 including a distributed AN302 and an AT 303.

In the distributed architecture shown in FIG. 3, the AN 302 comprisesaccess points (AP) and home agents (HA). AN 302 includes a plurality ofaccess points (APa 304, APb 306, APc 308) and home agent 310. Inaddition, AN 302 includes an IP cloud 312. The APs (304, 306, 308) arecoupled to the IP cloud via links (314, 316, 318), respectively. The IPcloud 312 is coupled to the HA 310 via link 320.

An AP includes a:

Network function (NF):

-   -   One per AP, and multiple NFs can serve a single AT.    -   A single NF is the IP layer attachment point (IAP) for each AT,        i.e., the NF to which the HA forwards packets sent to the AT. In        the example of FIG. 4, NF 336 is the current IAP for AT 303, as        shown by the line 322 in FIG. 4.    -   The IAP may change (L3 handoff) to optimize routing of packets        over the backhaul to the AT.    -   The IAP also performs the function of the session master for the        AT. (In some embodiments, only the session master can perform        session configuration, or change the session state.)    -   The NF acts as the controller for each of the TFs in the AP and        performs functions like allocating, managing and tearing down        resources for an AT at the TF.

Transceiver functions (TF) or sector:

-   -   Multiple per AP, and multiple TFs can serve a single AT.    -   Provides the air interface attachment for the AT.    -   Can be different for the forward and reverse links.    -   Changes (L2 handoff) based on radio conditions.

In AN 302 APa 304 includes NF 324, TF 326 and TF 328. In AN 302 APb 306includes NF 330, TF 332 and TF 334. In AN 302 APc 308 includes NF 336,TF 338 and TF 340.

An AT includes a:

-   -   Interface I_x presented to the mobile node (MN) for each NF in        the active set.    -   Mobile node (MN) to support IP layer mobility at the access        terminal.    -   APs communicate using a tunneling protocol defined over IP. The        tunnel is an IP-in-IP tunnel for the data plane and an L2TP        tunnel for the control plane.

Exemplary AT 303 includes a plurality of Interfaces (I_a 342, I_b 344,I_c 346) and MN 348. AT 303 can be, and sometimes is, coupled to AP_a304 via wireless link 350. AT 303 can be, and sometimes is, coupled toAP_b 306 via wireless link 352. AT 303, can be, and sometimes is,coupled to AP_c 308 via wireless link 354.

FIG. 4 illustrates an exemplary network 400 including a distributed AN402 and an AT 403.

In a centralized architecture shown in FIG. 4, the NF is no longerlogically associated with a single TF, so the AN comprises networkfunctions, access points and home agents. Exemplary AN 402 includes aplurality of NFs (404, 406, 408), a plurality of APs (AP_a 410, AP_b412, AP_c 414), HA 416 and IP cloud 418. NF 404 is coupled to IP cloud418 via link 420. NF 406 is coupled to IP cloud 418 via link 422. NF 408is coupled to IP cloud 418 via link 424. IP cloud 418 is coupled to HA416 via link 426. NF 404 is coupled to (AP_a 410, AP_b 412, AP_c 414)via links (428, 430, 432), respectively. NF 406 is coupled to (AP_a 410,AP_b 412, AP_c 414) via links (434, 436, 438), respectively. NF 408 iscoupled to (AP_a 410, AP_b 412, AP_c 414) via links (440, 442, 444),respectively.

AP_a 410 includes TF 462 and TF 464. AP_b 412 includes TF 466 and TF468. AP_c 414 includes TF 470 and TF 472.

Since an NF acts as the controller for a TF, and many NFs can belogically associated with a single TF, the NF controller for an AT,i.e., the NF communicating with an AT as a part of the active set,performs the functions of allocating, managing and tearing downresources for the TF at that AT. Therefore, multiple NFs may controlresources at a single TF, although these resources are managedindependently. In the example of FIG. 4, NF 408 is acting as an IAP forAT 403, as shown by the line 460.

The rest of the logical functions performed are the same as for thedistributed architecture.

Exemplary AT 403 includes a plurality of Interfaces (I_a 446, I_b 448,I_c 450) and MN 452. AT 403 can be, and sometimes is, coupled to AP_a410 via wireless link 454. AT 403 can be, and sometimes is, coupled toAP_b 412 via wireless link 456. AT 403 can be, and sometimes is, coupledto AP_c 414 via wireless link 458.

In systems like DO and 802.20, an AT obtains service from an AP bymaking an access attempt on an access channel of a particular sector(TF). The NF associated with the TF receiving the access attemptcontacts the IAP that is the session master for the AT and retrieves acopy of the AT's session. (The AT indicates the identity of the IAP byincluding an UATI in the access payload. The UATI may be used as an IPaddress to directly address the IAP, or may be used to look up theaddress of the IAP.) On a successful access attempt, the AT is assignedair interface resources such as a MAC ID and data channels tocommunicate with that sector.

Additionally, the AT may send a report indicating the other sectors itcan hear and their signal strengths. The TF receives the report andforwards it to a network based controller in the NF which in turnprovides the AT with an active set. For DO and 802.20 as they areimplemented today, there is exactly one NF that the AT can communicatewith (except during an NF handoff when there are temporarily two). Eachof the TFs in communication with the AT will forward the received dataand signaling to this single NF. This NF also acts as a network-basedcontroller for the AT and is responsible for negotiating and managingthe allocation and tear down of resources for the AT to use with thesectors in the active set.

The active set is therefore the set of sectors in which the AT isassigned air interface resources. The AT will continue to send periodicreports and the network based controller may add or remove sectors fromthe active set as the AT moves around in the network.

NFs in the active set will also fetch a local copy of the session forthe AT when they join the active set. The session is needed tocommunicate properly with the AT.

For a CDMA air link with soft handoff, on the uplink each of the sectorsin the active set may try to decode an AT's transmission. On thedownlink, each of the sectors in the active set may transmit to the ATsimultaneously, and the AT combines the received transmissions to decodethe packet.

For an OFDMA system, or a system without soft handoff, a function of theactive set is to allow the AT to switch quickly between sectors in theactive set and maintain service without having to make a new accessattempt. An access attempt is generally much slower than a switchbetween members of the active set, since the active set member alreadyhas the session and the air interface resources assigned to the AT.Therefore, an active set is useful to do handoff without affecting theQoS service of active applications.

When, an AT and the session master in the IAP negotiate attributes, oralternatively the state of the connection changes, the new values forthe attributes or the new state need to be distributed to each of thesectors in the active set in a timely manner to ensure optimal servicefrom each sector. In some cases, for example if the type of headerschanges, or security keys change, an AT may not be able to communicateat all with a sector until these changes are propagated to that sector.Thus every member of the active set should be updated when the sessionchanges. Some changes may be less critical to synchronize than others.

There are three main types of state or context found in the network foran AT that has an active connection:

Data state is the state in the network on the data path between the ATand the IAP or an NF during a connection. Data state includes thingssuch as header compressor state or RLP flow states which are verydynamic and difficult to transfer.

Session state is the state in the network on the control path betweenthe AT and the IAP that is preserved when a connection is closed.Session state includes the value of the attributes that are negotiatedbetween the AT and the IAP. These attributes affect the characteristicsof the connection and the service received by the AT. For example, an ATmay negotiate the QoS configuration for a new application and supply newfilter and flow specifications to the network indicating the QoS servicerequirements for the application. As another example the AT maynegotiate the size and type of the headers used in communication withthe AN. The negotiation of a new set of attributes is defined as asession change.

Connection state is the state in the network on the control path betweenthe AT and the IAP or an NF that is not preserved when a connectioncloses and the AT is idle. Connection state may include such informationas power control loop values, soft handoff timing, and active setinformation.

In an IAP or L3 handoff the three types of state may need to betransferred between the old IAP and the new IAP. If only an idle AT canmake an L3 handoff, then only the session state needs to be transferred.To support L3 handoff for an active AT, the data and connection statemay also need to be transferred.

Systems like DO and 802.20, make L3 handoff of the data state simple bydefining multiple routes (or data stacks), where the data state for eachroute is local to that route, i.e., the routes each have independentdata state. By associating each IAP with a different route, the datastate does not need to be transferred in a handoff. A further, evenbetter step, is to associate each NF with a different route in whichcase L3 handoff is completely transparent to the data state, except forpossible packet reordering.

Since the data state has multiple routes, the next logical step tosupport L3 handoff for an active AT is to move the control of theconnection state from the IAP and make it local to each NF in the activeset. This is done by defining multiple control routes (or controlstacks) and defining the air interface so that the control stacks areindependent and local to each NF. This may require that some of thenegotiating and managing the allocation and tear down of resources ofthe connection state is transferred to the AT since there is no longer asingle NF to manage all the members of the active set. It may also makesome additional requirements on the air interface design to avoid atight coupling between TFs—since different TFs may not share the sameNF—in the active set. For instance, to operate in an optimal way, it ispreferable to eliminate all tight synchronization between TFs that donot have the same NF, such as power control loops, soft handoff, etc.

Pushing the data and connection state down to the NFs eliminates theneed to transfer this state on a L3 handoff, and also should make theNF-to-NF interface simpler.

The system therefore defines multiple independent data and controlstacks (called interfaces in FIG. 3 and FIG. 4), in the AT tocommunicate with different NFs as needed, as well as the addressingmechanisms for the AT and TFs to logically distinguish between thesestacks.

Fundamentally, some session state (QoS profile, security keys, attributevalues, etc.) cannot be made local to an NF (or IAP) because it is tooexpensive to negotiate every time there is a NF (or a L3) handoff. Alsothe session state is relatively static and easy to transfer. What isneeded are mechanisms to manage and update the session state as itchanges and during IAP handoff where the session master moves.

Optimizing the session state transfer for L3 handoff is a useful featurefor every system regardless of the network architecture since itsimplifies network interfaces and should also improve the seamlessnessof handoff.

Control Vs. Awareness of Handoff

A separate but related issue is the AT control of L3 handoff. Today, insystems like DO and 802.20, the AT is aware of the L3 handoff since itallocates and tears down local stacks, but it has no control of when L3handoff occurs. This is called network-based mobility management. Thequestion is whether to make AT the handoff controller, i.e., to use ATbased mobility management?

To support fault tolerance and load balancing, the network needs eitherto be able to make the handoff or have a mechanism to signal to the ATto do a handoff. Thus if AT based mobility management is used, thenetwork still needs a mechanism to indicate when it should occur.

AT based mobility management has some obvious advantages, such asallowing for a single mechanism for inter and intra technology, orglobal and local mobility. It also simplifies the network interfacesfurther by not requiring the network elements to determine when to dohandoff.

The primary reason systems like DO and 802.20 use network based mobilityis that AT based mobility is not optimized to work fast enough tosupport voice. A secondary reason is the tunneling overhead introducedby terminating the mobile IP tunnels (for MIPv6) in the AT. The mobilitylatency can be solved by forwarding data using tunnels between thecurrent and previous forward link serving sector, as well as possiblyusing bicasting, where the data is sent to multiple NFs in the activeset simultaneously.

L2 and L3 Handoff

-   -   In SimpleRAN, there are two types of handoff. For example, Layer        2 or L2 handoff refers to changing of the forward link or        reverse link serving sector (TF) and L3 handoff refers to        changing of the IAP. L2 handoff should be as fast as possible in        response to changing radio conditions. Systems like DO and        802.20 use PHY layer signaling to make L2 handoff fast.

L2 handoff is transfer of the serving sector TF for the forward (FL) orreverse (RL) links. A handoff occurs when the AT selects a new servingsector in the active set based on the RF conditions seen at the AT forthat sector. The AT performs filtered measurements on the RF conditionsfor the forward and reverse links for all sectors in the active set. Forinstance, in 802.20 for the forward link the AT can measure the SINR onthe acquisition pilots, the common pilot channel (if present), and thepilots on the shared signaling channel, to select its desired FL servingsector. For the reverse link, the AT estimates the CQI erasure rate foreach sector in the active set based on the up/down power controlcommands to the AT from the sector.

L2 handoff is initiated when the AT requests a different FL or RLserving sector via a reverse link control channel. Dedicated resourcesare assigned at a TF when it is included in the active set for an AT.The TF is already configured to support the AT before the handoffrequest. The target serving sector detects the handoff request andcompletes the handoff with the assignment of traffic resources to theAT. The forward link TF handoff requires a round trip of messagingbetween the source TF or IAP and target TF in order to receive data forthe target TF to transmit. For reverse link TF handoff, the target TFmay immediately assign resources to the AT.

L3 handoff is the transfer of the IAP. L3 handoff involves a HA bindingupdate with the new IAP and requires a session transfer to the new IAPfor the control-plane. L3 handoff is asynchronous to L2 handoff in thesystem so that L2 handoff is not limited by MIPv6 handoff signalingspeed.

L3 handoff is supported over the air in the system by defining anindependent route to each NF. Each flow provides multiple routes fortransmission and reception of higher layer packets. The route indicateswhich NF processed the packet. For example, one NF may be associated atthe TF and over the air as Route A, while another NF may be associatedwith Route B. A serving TF can simultaneously send packets to an AT fromboth Route A and Route B. i.e., from both NFs, using a separate andindependent sequence space for each.

There are two key ideas in the system design to ensure the QoS treatmentfor a mobile and its traffic is retained over each handoff mode:Decoupling of L2 and L3 handoff.

Reserving air interface resources and fetching the session at the targetNF or TF before the handoff occurs to minimize the data flowinterruption during the handoff. This is done by adding the target TFand NF to the active set.

The system is designed to separate L2 and L3 handoff in order to allowthe system to support EF traffic during high rates of L2 handoff. L3handoff requires a binding update, which is limited to a rate of 2 to 3per second. In order to allow a faster L2 handoff rate of 20 to 30 Hz,L2 and L3 handoff are designed to be independent and asynchronous.

For L2 handoff, the active set management allows all the TFs in theactive set to be configured and dedicated resources assigned in order tobe ready to serve the AT in the event of an L2 handoff.

Consider a Mobile Wireless Communication System with multiple accesspoints (AP) that provide service to access terminals (AT). Many systemshave an active set, which is a set of APs that have assigned resourcesto the AT. At a given point in time, an AT may be within range of radiocommunication with one of the APs, or for the purpose of battery poweroptimization and radio interference reduction, may communicate only withone carefully selected AP (serving AP). The problem considered here isthe delivery of messages and data between the various APs in the system,such that the serving AP can deliver messages to and from the AT.

APs can exchange data over an L2TP (layer two tunneling protocol)tunnel. If AP1 has to send a message or data to the AT, while AP2 is theserving AP, then AP1 first uses the L2TP tunnel to deliver the packet toAP2, and AP2 delivers this packet to the AT using a mechanism includingthe use of an identifier bit, e.g., a reprocess bit.Similarly, if the AT has to send a message or data to AP1, while AP2 isserving, it sends the message to AP2 with a remote bit set, and AP2sends this packet to AP1 via the L2TP tunnel.The L2TP header includes the following fields

-   -   1. UserID: This is the address of the user to which the L2TP        packet is addressed    -   2. ForwardOrReverse: This field identifies if the AT is the        destination or the source of the packet.    -   3. FlowID: In one design, this field may be present only in        forward link packets (packets destined to the AT), and it        identifies the flow that the serving AP should use to deliver        the packet to the AT    -   4. SecurityField: In one design, this field may be present only        in reverse link packets (packets originated at the AT). The        SecurityField may include an IsSecure bit, a KeyIndex field (to        identify the keys used for security operation) and a CryptoSync        field.        In an aspect, forward Link L2TP Packets are communicated. Here        we describe the process used by an AP to send and receive a        forward link L2TP packet.        An AP sends a forward link L2TP packet when it has data or a        message to send to the AT. The AP forms the appropriate header        and sends the L2TP packet to the serving AP (or if it does not        know the identity of the serving AP, possibly by routing the        packet through a central node—the IAP).        When an AP receives a forward link L2TP packet, it does the        following steps    -   1. If the AP is not serving for the given UserID (in the L2TP        header), it forwards the packet to the current serving AP        (possibly by routing the packet through a central node—the IAP)    -   2. If the AP is serving for the given UserID, it delivers the        packet to the AT using the RLP flow and associated QoS        attributes for the given FlowID (in the L2TP header).

In an aspect, reverse Link L2TP Packets are communicated. Here wedescribe the process used by an AP to send and receive a reverse linkL2TP packet. An AP sends a reverse link L2TP packet when it receives apacket from the AT, and the remote bit is set for that packet. The firststep for the AP sending the L2TP packet is address determination.

Address Determination: If the remote bit for the packet is set, thepacket also includes an address field to identify which AP this packetshould be delivered to (target AP). The receiving AP maps the addressfield to the IP address of the AP. This mapping may be established by

-   -   1. An AT assisted method wherein messages describing a mapping        are sent from the AT to the AP, and the mapping information is        then used by the AP to map between the address used over the        airlink and the IP address.    -   2. A network assisted method whereby mapping information        provided by a central entity or by the target AP is used.    -   3. A PilotPN based method. In this case the address field may        simply be equal to the PilotPN (or some upper bits of the        PilotPN) of the AP corresponding to the address. The receiving        AP knows the PilotPN and IP addresses of all neighboring APs as        part of the network configuration (which itself may be network        assisted) and uses this information to map between the PN based        address and corresponding IP address.    -   4. An IAP address method where a special address type is used by        the AT to identify the AP which is the Internet attachment point        for the AT. Each AP in an active set of APs corresponding to an        AT knows the IP address of the IAP for the particular AT and can        map between the IAP address and IP address of the AT's IAP.

After address determination, the AP sending the L2TP packet may alsoinsert security related fields if needed, and as determined by thesecurity design. When an AP receives a reverse link L2TP packet, it doesthe following steps

-   -   1. If the AP is not serving the given UserID indicated in a        received packet (in the L2TP tunnel), it ignores the packet    -   2. If the AP is serving the given UserID of the received packet,        it processes the packet as if the packet were received from its        own MAC layer. The processing of the packet may depend on the        SecurityField received in the L2TP tunnel.

FIG. 5 is a flowchart 500 of an exemplary method of operating an accesspoint to communicate information to an access terminal in accordancewith various embodiments. Operation starts in step 502 where the accesspoint is powered on and initialized. The access point performing themethod of flowchart 500 is, e.g., a serving access point which has anactive airlink with the access terminal. Thus the access point is aserving access point from the perspective of the access terminal. Steps504 and/or 506 are performed in some embodiments, but are omitted inother embodiments. Flow will be described as if both steps 504 and 506are included; however, it is to be understood that operation flow canbypass an omitted step.

Operation proceeds from start step 502 to step 504. In step 504 theaccess point, e.g., the serving access point, receives a packet from aremote access point, said received packet including an IP addresscorresponding to the remote access point and information to becommunicated to the access terminal. Then, in step 506 the access point,e.g., the serving access point, retrieves from an IP address to PN codemapping information database, PN code address information correspondingto said IP address of the remote access point. Operation proceeds fromstep 506 to step 508.

In step 508 the access point, e.g., the serving access point, generatesa packet, said packet including a PN code address identifying an accesspoint, e.g., said remote access point, and information to becommunicated. Step 508 includes sub-step 510, in which the access pointperforming the method of flowchart 500, e.g., the serving access point,determines the PN code address from another address, e.g., an IPaddress, corresponding to said access point, e.g., said remote accesspoint, said another address including more bits than said PN codeaddress. In some embodiments, sub-step 510 includes sub-step 512. Insub-step 512, the access point performing the method of flowchart 500,e.g., the serving access point, determines the PN code addresscorresponding to the remote access point from the retrieved PN codeaddress information corresponding to said IP address of said remoteaccess point. Then, in step 512, the access point, e.g., the servingaccess point, transmits the generated packet over an airlink.

In some embodiments, the PN code address information includes the PNcode address corresponding to the remote access point, and the step ofperforming an address determination operation includes using theretrieved PN code address as said PN code address in the transmittedpacket. In some other embodiments, the retrieved PN code addressinformation includes a value from which the PN code addresscorresponding to said remote access point can be derived by apredetermined function, and determining the PN code addresscorresponding to the remote device includes using said predeterminedfunction to generate said PN code address from the value included in theretrieved PN code address information. In some embodiments, thedetermined PN code address is a portion of a Pilot PN code used by saidremote access point and generating a packet includes including in saidgenerated packet the information included in said received packet.

FIG. 6 is a flowchart 600 of an exemplary method of operating an accesspoint to communicate with a remote access point. Operation starts instep 602, where the access point is powered on and initialized andproceeds to step 604. In step 604, the access point receives informationindicating PN codes used by other access points in the system. Then, instep 606 the access point stores PN code information corresponding toother nodes in the system with corresponding long addressescorresponding to the other nodes. Operation proceeds from step 606 tostep 608.

In step 608, the access point, e.g., a serving access point from theperspective of an access terminal, receives a packet from the accessterminal, said packet including a PN code address and information to becommunicated to a remote device. Operation proceeds from step 608 tostep 610. In step 610, the access terminal determines a long addresscorresponding to the said PN code address to be used for communicating apacket to said remote device, said long address including more bits thansaid PN code address. Step 610 includes sub-step 612 in which the accesspoint retrieves, from an IP address to PN code address mappinginformation database, an IP address corresponding to a PN code address.Operation proceeds from step 610 to step 614. In step 614 the accesspoint sends the information to be communicated with the long address tosaid remote device. In some embodiments, sending the information to becommunicated, with the long address, to said remote device includessending the received information to said remote access point using thedetermined IP address as a destination identifier in a header used forrouting said packet to said remote access point through a Layer 2tunnel.

In some embodiments, the stored PN code information includes a valuewhich can be determined in a predetermined known manner from a PN codeaddress. In some embodiments, the stored PN code information includesthe PN code address corresponding to the IP address of the remote accesspoint.

FIG. 7 is a drawing of an exemplary access point 700 in accordance withvarious embodiments. The access point 700 communicates information, viaa wireless link, with an access terminal for which it is acting as aserving access point. Exemplary access point 700 includes a wirelessreceiver module 702, a wireless transmitter module 704, a processor 706,a network interface module 708 and memory 710 coupled together via a bus712 over which the various elements may interchange data andinformation. Memory 710 includes routines 718 and data/information 720.The processor 706, e.g., a CPU, executes the routines 718 and uses thedata/information 720 in memory 710 to control the operation of theaccess point and implement methods, e.g., a method in accordance withflowchart 500 of FIG. 5 and/or flowchart 600 of FIG. 6.

Wireless receiver module 702, e.g., an OFDM and/or CDMA receiver, iscoupled to receiver antenna 714 via which the access point receivesuplink signals from access terminals. Wireless receiver module 702receives a packet from an access terminal, said received packetincluding a PN code address and information to be communicated to aremote device, e.g., a remote access point.

Wireless transmitter module 704, e.g., an OFDM and/or CDMA transmitter,is coupled to transmit antenna 716 via which the access point transmitsdownlink signals to access terminals. Wireless transmitter module 704transmits, over a wireless communications link, downlink packets, e.g.,a generated downlink packet from module 724 including a PN code addressas part of a header and a packet payload portion including informationto be communicated.

In some embodiments multiple antennas and/or multiple antenna elementsare used for reception. In some embodiments multiple antenna and/ormultiple antenna elements are used for transmission. In some embodimentsat least some of the same antennas or antenna elements are used for bothtransmission and reception. In some embodiments, the access point usesMIMO techniques.

Network interface module 708 couples the access point 700 to othernetwork nodes, e.g., other access points, AAA nodes, home agent nodes,etc., and/or the Internet via network link 709. In various embodiments,inter-AP tunnels, e.g. Layer 2 Tunneling Protocol tunnels, areestablished over the backhaul network through network interface module708 and the tunnel path includes network link 709. Network interfacemodule 708 receives a packet from a remote device e.g., a remote accesspoint, via a network connection, e.g., link 709, said packet including along address and information to be communicated.

Routines 718 includes a long address to PN code address mapping module722, a downlink packet generation module 724, a database updating module726, a PN code address to long address mapping module 728, and atunneled packet generation module 730. Data/information 720 includes anaddress information database 732 and access terminal state information742. Address information database 732, which is accessible to the longaddress to PN code address mapping module 722, includes storedinformation associating long addresses with corresponding PN codeaddress information. Address information database 732 includes aplurality of sets of information corresponding to different accesspoints in the communications system (access point 1 information 733, . .. , access point n information 735). Access point 1 information 733includes long address 1 734 and corresponding PN code addressinformation 1 736. Access point n information 735 includes long addressn 738 and corresponding PN code address information n 740. In someembodiments the long addresses (734, 738) are IP addresses. In variousembodiments, a PN code address is based on a pilot PN code used by anaccess point having the long address corresponding to the PN codeaddress. In various embodiments, the long address is an address used forrouting packets between access points, e.g., between a remote accesspoint and a serving access point, through a layer 2 tunnel, e.g., alayer 2 tunneling protocol tunnel, and the PN code information includesa PN code used for communicating packets over an airlink. Accessterminal state information includes state information corresponding to aplurality of access terminals, e.g., access terminals having an activewireless link with the access point 700 (access terminal 1 stateinformation 744, . . . , access terminal N state information 746).

Long address to PN code address mapping module 722 determines a PN codeaddress corresponding to a long address, said PN code address for useover a wireless communications link, said PN code address includingfewer bits than said long address. Downlink packet generation module 724generates a packet including said PN code address and said informationto be communicated.

PN code address to long address mapping module 728 determines a longaddress corresponding to a PN code address to be used for communicatinginformation to a remote device, e.g., a remote access point, said longaddress including more bits than said PN code address. Tunneled packetgeneration module 730 generates a packet to be sent to a remote device,e.g., a remote access point, said tunneled packet generation module 730generating a packet including: i) a long address determined from a PNcode address included in a received packet and ii) information to becommunicated which was included in the received packet that included theshort address used to determine the long address.

FIG. 8 is a flowchart 800 of an exemplary method of operating an accessterminal to communicate information in accordance with variousembodiments. Operation starts in step 802 where the access terminal ispowered on and initialized and proceeds to step 804. In step 804, theaccess terminal receives a signal from a device, e.g., a pilot signalfrom a remote access point. Then, in step 806, the access terminalgenerates a PN code address from the received signal. In variousembodiments step 806 includes sub step 808 in which the access terminaluses a predetermined function to generate the PN code address from apilot PN code determined from the received pilot signal. In some suchembodiments, the predetermined function uses a full PN pilot code as thePN code address of the remote device. In some other embodiments, thepredetermined function uses a portion of a pilot PN code as the codeaddress of the remote device, said portion being less than the fullpilot PN code.

Operation proceeds from step 806 to step 810. In step 810 the accessterminal stores in an airlink to IP address information database,information mapping between an IP address corresponding to said device,e.g., said remote access point, and said PN code address generated instep 806.

Operation proceeds from step 810 to step 812, in which the accessterminal determines if the access terminal has a non-PN based airlinkaddress for said device, e.g., said remote access point. In variousembodiments, step 812 includes sub-step 814 in which the access terminalchecks to determine if said access terminal has one of i) apredetermined reserved address; ii) an address supplied by the accessterminal to the first access point to be used for communications over anairlink to said first access point for packets directed to said remoteaccess point; and iii) a network supplied address to be used for packetscommunicated over an airlink to said remote access point.

Operation proceeds from step 812 to step 816. In step 816, flow isdirected as a function of whether or not one or more non-PN basedairlink addresses were found for the device, e.g., for the remote accesspoint. If a non-PN based address was not found in step 812, thenoperation proceeds from step 816 to step 818; otherwise operationproceeds from step 816 to step 820.

Returning to step 818, in step 818, the access terminal generates apacket including said PN code address, said packet being directed tosaid device, e.g., to said remote access point. Operation proceeds fromstep 818 to step 822.

Returning to step 820, in step 820, the access terminal generates apacket including a non-PN based airlink address, said packet beingdirected to said device, e.g., to said remote access point. Operationproceeds from step 820 to step 822.

In step 822, the access terminal transmits said generated packet to afirst communications device, e.g., a first access point, over a wirelesscommunications link. The transmitted packet is directed to said remotedevice, e.g., to said remote access point. The first access point iscoupled to the device, e.g., the remote access point, via a backhaulnetwork providing a communications link.

FIG. 9 is a flowchart 900 of an exemplary method of operating an accessterminal to receive information from a remote device through an accesspoint. Operation starts in step 902 where the access terminal is poweredon and initialized and proceeds to step 904. In step 904, the accessterminal receives a pilot signal from a remote device. Then, in step 906the access terminal generates a pilot code address from said receivedpilot signal. Step 906 includes sub-step 908 in which the accessterminal uses a predetermined function to generate the pilot codeaddress from a pilot PN code determined from the received pilot signal.In some embodiments, the predetermined function uses the full pilot PNcode as the PN code address of the remote device. In some otherembodiments, the predetermined function uses a portion of the pilot PNcode as the PN code address of the remote device, said portion beingless than the full pilot PN code. Operation proceeds from step 906 tostep 910.

In step 910, the access terminal stores the pilot address generated fromthe received pilot signal in a database of information used for mappingbetween PN code addresses and long addresses. In various embodiments,storing the pilot address generated from the received pilot signal in adatabase of information includes storing said pilot code address with along address corresponding to said remote device. In some suchembodiments, the long address is an IP address corresponding to theremote device.

Operation proceeds from step 910 to step 912. In step 912, the accessterminal receives from said access point a packet including a PN codeaddress corresponding to said remote device and information from saidremote device. Then, in step 914, the access terminal identifies theremote device which provided the information from said PN code addressand stored information relating the received PN code address to anaccess point.

In one exemplary embodiment, the remote device is a remote access pointand the remote device previously served as the access terminal's activenetwork point of attachment, and the access point serves as the accessterminal's current active network point of attachment.

FIG. 10 is a drawing of an exemplary access terminal 1000 in accordancewith various embodiments. Exemplary access terminal 1000 can, andsometimes does, communicate information to a remote device through anaccess point. Exemplary access terminal 1000 includes a wirelessreceiver module 1002, a wireless transmitter module 1004, a processor1006, user J/O devices 1008 and memory 1010 coupled together via a bus1012 over which the various elements may interchange data andinformation. Memory 1010 includes routines 1018 and data/information1020. The processor 1006, e.g., a CPU, executes the routines 1018 anduses the data/information 1020 in memory 1010 to control the operationof the access terminal and implement methods, e.g., the methods offlowchart 800 of FIG. 8 and flowchart 900 of FIG. 9.

Wireless receiver module 1002, e.g., a CDMA or OFDM receiver, is coupledto receive antenna 1014 via which the access terminal 1000 receivesdownlink signals from access points. Wireless receiver module 1002receives a packet communicated over the air to said access terminalwhich includes a PN code address identifying the source of informationincluded in the received packet, e.g., received packet 1058.

Wireless transmitter module 1004, e.g., a CDMA or OFDM transmitter, iscoupled to transmit antenna 1016 via which the access terminal 1000transmits uplink signals to access points. Wireless transmitter module1004 transmits a generated packet, e.g., generated packet 1052, over theair to an access point.

In some embodiments, the same antenna is used for transmission andreception. In some embodiments multiple antennas and/or multiple antennaelements are used for reception. In some embodiments multiple antennaand/or multiple antenna elements are used for transmission. In someembodiments at least some of the same antennas or antenna elements areused for both transmission and reception. In some embodiments, theaccess terminal uses MIMO techniques.

User I/O device 1008 include, e.g., microphone, keyboard, keypad,switches, camera, speaker, display, etc. User I/O devices 1008 allow auser of access terminal 1000 to input data/information, access outputdata/information, and control at least some functions of the accessterminal 1000, e.g., initiate a communications session with a peer node,e.g., another access terminal.

Routines 1018 include a PN code address determination module 1022, apacket generation module 1024, a received packet source identificationmodule 1026, and an address database updating module 1031. In someembodiments, routines 1018 include a non-PN based address availabilitymodule 1027, and an address type decision module 1029. Data/information1020 includes a received pilot signal 1028, a corresponding PN code ofthe received pilot signal 1030 and a corresponding determined PN codeaddress 1032. Data/information 1020 also includes an address informationdatabase 1034 which includes address mapping information correspondingto a plurality of access points (access point 1 information 1036, . . ., access point n information 1038). Address information database 1034is, e.g., an airlink to IP address information database. Access point 1information 1036 includes long address 1 1040 and corresponding PN codeaddress 1 1042. Access point n information 1038 includes long address n1044 and corresponding PN code address n 1046. Database 1034 stores PNcode addresses determined from the received pilot signal. In someembodiments, the stored PN code addresses (1042, . . . , 1046) are thePN codes of the pilot signal from which the PN code address wasdetermined. For example, in some embodiments, PN code of pilot signal1030 is the same as determined PN code address 1032. In someembodiments, a stored PN code address is derived from the PN code of thepilot signal from which the PN code address is determined according to apredetermined function. For example, determined PN code address 1032 isderived from PN code of pilot signal 1030 and the two values may be andsometimes are different.

In some embodiments the address information database 1034 may, andsometimes does, include one or more alternative non-PN based alternativeaddresses corresponding to a long address. For example, access point ninformation 1038, in some embodiments, includes non-PN code basedalternative address n 1047 which also corresponds to long address n1044. A non-PN code based address such as non-PN code based alternativeaddress n 1047 is, e.g., one of a predetermined reserved address, anaddress supplied by access terminal 1000 to a first access point to beused for communications over an airlink with said first access point forpackets directed to a remote access point, and a network suppliedaddress to be used for packets communicated over an airlink to saidremote access point.

Data/information 1020 also includes access terminal state information1048, e.g., information including a list of access points with which theaccess terminal has a current active link. Data information 1020 alsoincludes a destination address 1050 and a corresponding generated packet1052. The destination address is, e.g., a long address such as an IPaddress corresponding to an AP. The generated packet 1052 includes a PNcode address 1054, e.g., the corresponding PN code address todestination address 1050, and payload information 1056. Data/information1020 also includes a received packet 1058 and a corresponding identifiedsource address 1064. Received packet 1058 includes a PN code address1060 and payload information 1062. The identified source address 1064 isthe long address matching the PN code address 1060.

Packet generation module 1024 generates a packet, e.g., generated packet1052, including an PN code address and information to be communicated toa remote device. In some embodiments, packet generation module 1024, attimes, generates a packet including a non-PN code based address andinformation to be communicated to a remote device. In some suchembodiments, packet generation module 1024 includes a PN code basedpacket generation sub-module and a non-PN code based packet generationsub-module.

PN code address determination module 1022 determines, e.g., generates, aPN code address from a pilot signal, said PN code address correspondingto an access point from which the pilot signal was received. Forexample, corresponding to one access point, PN code addressdetermination module 1022 determines PN code address 1032 from receivedpilot signal 1028. In some embodiments, determining, e.g., generating aPN code address includes using a predetermined function to generate thePN code address from a pilot PN code determined from a received pilotsignal. In some such embodiments, the predetermined function uses a fullpilot PN code as the PN code address of the remote device from which thepilot signal was received. In some other embodiments, the predeterminedfunction uses a portion of a pilot PN code as the PN code address of theremote device, said portion being less than the full pilot PN code.

Received packet source identification module 1026 identifies a source ofa received packet using the address information database 1034. Forexample, received packet source identification module 1026 processesreceived packet 1058, examines the PN code address, and determines fromthe address information database 1034 the source of the information,e.g., the long address, associated with the PN code address 1060.Identified source address 1064 is an output of received packet sourceidentification module 1026 and is one of the long addresses (1040, . . ., 1044) in the database 1034.

Address database updating module 1031 updates and maintains addressinformation database 1034, e.g., storing in address information database1034 information mapping between an IP address corresponding to a remotedevice and a PN code address. For example, determined PN code address1032 is stored in address information database 1034 and associated withits access point and corresponding long address.

Non-PN based address availability module 1027 determines if accessterminal 1000 has a non-PN code based airlink address for a remoteaccess point. In some embodiments, the packet generation module 1024uses the PN code address to generate a packet when the availabilitymodule 1027 determines that a non-PN code based address is not availablefor a remote access point; otherwise the packet generation module 1024uses one of the available non-PN code based addresses. Address typedecision module 1029 determines which type of address to use. In someembodiments, the address type decision module 1029 decides whether touse a PN based address or a non-PN based address. In some embodiments,the address type decision module 1029 decides which type of non-PN basedaddress to use when a plurality of non-PN based alternative addressesare available. In some embodiments, different types of alternativeaddresses are associated with different portions of a communicationssystem, different devices and/or different priority levels.

In various embodiments, nodes described herein are implemented using oneor more modules to perform the steps corresponding to one or moremethods of the aspect, for example, signal processing, messagegeneration and/or transmission steps. Thus, in some embodiments variousfeatures are implemented using modules. Such modules may be implementedusing software, hardware or a combination of software and hardware. Manyof the above described methods or method steps can be implemented usingmachine executable instructions, such as software, included in a machinereadable medium such as a memory device, e.g., RAM, floppy disk, compactdisc, DVD, etc. to control a machine, e.g., general purpose computerwith or without additional hardware, to implement all or portions of theabove described methods, e.g., in one or more nodes. Accordingly, amongother things, the aspect is directed to a machine-readable mediumincluding machine executable instructions for causing a machine, e.g.,processor and associated hardware, to perform one or more of the stepsof the above-described method(s).

In various embodiments nodes described herein are implemented using oneor more modules to perform the steps corresponding to one or moremethods, for example, signal processing, message generation and/ortransmission steps. Some exemplary steps include transmitting aconnection request, receiving a connection response, updating a set ofinformation indicating an access point with which an access terminal hasan active connection, forwarding a connection request, forwarding aconnection response, determining resource assignment, requestingresources, updating resources, etc. In some embodiments various featuresare implemented using modules. Such modules may be implemented usingsoftware, hardware or a combination of software and hardware. Many ofthe above described methods or method steps can be implemented usingmachine executable instructions, such as software, included in a machinereadable medium such as a memory device, e.g., RAM, floppy disk, compactdisc, DVD, etc. to control a machine, e.g., general purpose computerwith or without additional hardware, to implement all or portions of theabove described methods, e.g., in one or more nodes. Accordingly, amongother things, various embodiments are directed to a machine-readablemedium including machine executable instructions for causing a machine,e.g., processor and associated hardware, to perform one or more of thesteps of the above-described method(s).

In some embodiments, the processor or processors, e.g., CPUs, of one ormore devices, e.g., communications devices such as access terminalsand/or access points, are configured to perform the steps of the methodsdescribed as being performed by the communications device. Theconfiguration of the processor may be achieved by using one or moremodules, e.g., software modules, to control processor configurationand/or by including hardware in the processor, e.g., hardware modules,to perform the recited steps and/or control processor configuration.Accordingly, some but not all embodiments are directed to a device,e.g., communications device, with a processor which includes a modulecorresponding to each of the steps of the various described methodsperformed by the device in which the processor is included. In some butnot all embodiments a device, e.g., communications device, includes amodule corresponding to each of the steps of the various describedmethods performed by the device in which the processor is included. Themodules may be implemented using software and/or hardware.

Numerous additional variations on the methods and apparatus describedabove will be apparent to those skilled in the art in view of the abovedescriptions. Such variations are to be considered within scope. Themethods and apparatus of various embodiments may be, and in variousembodiments are, used with CDMA, orthogonal frequency divisionmultiplexing (OFDM), and/or various other types of communicationstechniques which may be used to provide wireless communications linksbetween access nodes and mobile nodes. In some embodiments the accessnodes are implemented as base stations which establish communicationslinks with mobile nodes using OFDM and/or CDMA. In various embodimentsthe mobile nodes are implemented as notebook computers, personal dataassistants (PDAs), or other portable devices includingreceiver/transmitter circuits and logic and/or routines, forimplementing the methods of various embodiments.

What is claimed is:
 1. A method of communicating information to anaccess terminal, the method comprising: determining a PN (Pseudo-randomNoise) code address from an IP (Internet Protocol) address correspondingto a remote access point, said IP address including more bits than saidPN code address; generating, by a serving access point, a packetincluding the PN code address identifying the remote access point andsaid packet further including information to be communicated to saidaccess terminal; and transmitting said generated packet over an airlinkto the access terminal.
 2. The method of claim 1, wherein the servingaccess point which has an active airlink with said access terminal, themethod further comprising, prior to generating said packet: receiving apacket from said remote access point, said received packet including anIP address corresponding to said remote access point and the informationto be communicated to the access terminal; and retrieving, from an IPaddress to PN code address mapping information database, PN code addressinformation corresponding to said IP address of said remote accesspoint.
 3. The method of claim 2, wherein performing the PN code addressdetermination operation further includes: determining the PN codeaddress corresponding to said remote access point from said retrieved PNcode address information corresponding to said IP address of said remoteaccess point.
 4. The method of claim 3, wherein said PN code addressinformation includes the PN code address corresponding to said remoteaccess point; and wherein said step of performing the PN code addressdetermination operation includes using the retrieved PN code address assaid PN code address included in the transmitted packet.
 5. The methodof claim 3, wherein said retrieved PN code address information includesa value from which the PN code address corresponding to said remoteaccess point can be derived by a predetermined function; and whereindetermining the PN code address corresponding to the remote access pointincludes using said predetermined function to generate said PN codeaddress from the value included in the retrieved PN code addressinformation.
 6. The method of claim 5, wherein the determined PN codeaddress is a portion of a Pilot PN code used by said remote accesspoint; and wherein generating the packet includes including in saidgenerated packet the information included in said received packet.
 7. Anapparatus comprising: a processor for use in a serving access point, theprocessor configured to: determine a PN (Pseudo-random Noise) codeaddress from an IP (Internet Protocol) address corresponding to a remoteaccess point, said IP address including more bits than said PN codeaddress; generate a packet including the PN code address identifying theremote access point and said packet further including information to becommunicated to an access terminal; and transmit said generated packetover an airlink to the access terminal.
 8. The apparatus of claim 7,wherein the serving access point has an active airlink with said accessterminal, the processor is further configured to, prior to generatingsaid packet: receive a packet from said remote access point, saidreceived packet including an IP address corresponding to said remoteaccess point and the information to be communicated to the accessterminal; and retrieve, from an IP address to PN code address mappinginformation database, PN code address information corresponding to saidIP address of said remote access point.
 9. The apparatus of claim 8,wherein said processor, in performing the PN code address determinationoperation, is further configured to: perform the PN code addressdetermination operation by determining the PN code address correspondingto said remote access point from said retrieved PN code addressinformation corresponding to said IP address of said remote accesspoint.
 10. A method of operating an access point to communicateinformation to a remote access point, the method comprising: receiving apacket from an access terminal, said packet including a PN(Pseudo-random Noise) code address and information to be communicated toa remote device; determining, from an IP address to PN code addressmapping information database, an IP (Internet Protocol) addresscorresponding to said PN code address to be used for communicating thepacket to said remote device, said IP address including more bits thansaid PN code address; and sending said packet including said informationto be communicated, with the IP address, to said remote device.
 11. Themethod of claim 10, further comprising, prior to said step ofdetermining the IP address corresponding to said PN code address,receiving information indicating PN codes used by other access points ina system; and storing PN code information corresponding to the otheraccess points in said system with corresponding IP addressescorresponding to said other access points.
 12. The method of claim 11,wherein said stored PN code information includes a value which can bedetermined in a predetermined known manner from the PN code address. 13.The method of claim 11, wherein said stored PN code information includesthe PN code address corresponding to the IP address of said remoteaccess point.
 14. The method of claim 11, wherein sending saidinformation to be communicated, with the IP address, to said remotedevice includes sending the received information to said remote accesspoint using the determined IP address as a destination identifier in aheader used for routing said packet to said remote access point througha Layer 2 tunnel.